Biphenotypic B220⁺GR-1/MAC-1⁺ cells generated from PAX5-transduced LSK cells have an immature myeloid morphology. Typical morphology of May-Grünwald– and Giemsa-stained FACS-purified GFP⁺ control (A) and PAX5-transduced (B) biphenotypic GFP(PAX5)⁺B220⁺GR-1/MAC-1⁺ cells from liquid culture at 24 days after transduction. Open triangles indicate immature granulocytes (promyelocytes, myelocytes), whereas filled triangles point at more mature forms of granulocytes (metamyelocytes, band and segmented forms). Original magnification × 500.